We investigated the effects of Brazilian green propolis and
its constituents against white light- or UVA-induced cell damage in mouse
retinal cone-cell line 661W or human skin-derived fibroblast cells (NB1-RGB).

Methods. Cell damage was induced by 3,000lx white light for
24 h or 4/10 J/cm(2) UVA exposure. Cell viability was assessed by Hoechst33342
and propidium iodide staining or by tetrazolium salt (WST-8) cell viability
assay. The radical scavenging activity of propolis induced by UVA irradiation
in NB1-RGB cells was measured using a reactive-oxygen-species- (ROS-) sensitive
probe CM-H2DCFDA. Moreover, the effects of propolis on the UVA-induced
activation of p38 and extracellular signal-regulated kinase (ERK) were examined
by immunoblotting.

Results. Treatment with propolis and two dicaffeoylquinic
acids significantly inhibited the decrease in cell viability induced by white
light in 661W. Propolis and its constituents inhibited the decrease in cell
viability induced by UVA in NB1-RGB. Moreover, propolis suppressed the
intracellular ROS production by UVA irradiation. Propolis also inhibited the
levels of phosphorylated-p38 and ERK by UVA irradiation.

Conclusion. Brazilian green propolis may become a major therapeutic
candidate for the treatment of AMD and skin damage induced by UV irradiation.